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M2-PK: a target of the HPV-16 E7 oncoprotein in NRK cells
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In normal rat kidney cells (NRK cells) a second oncoprotein (ras) is necessary for transformation.

Explanation:
The non-transformed normal rat kidney cells proliferate. Total pyruvate kinase activity is low and M2-PK is mainly in the less active dimeric form.
Ras expression leads to an inhibition of cell proliferation. Total pyruvate kinase activity increases and M2-PK is shifted to the highly active tetrameric form.
When both ras and E7 are expressed the cells are transformed. Total pyruvate kinase activity is not changed but M2-PK is shifted to the less active dimeric form.
The tetrameric form of M2-PK is correlated with a high (ATP+GTP) : (UTP+CTP) ratio which means that ATP and GTP levels are high and UTP and CTP levels are low.
The dimeric form is correlated with a low (ATP+GTP) : UTP+CTP) ratio, which means that UTP and CTP levels are high and ATP and GTP levels are low.
References
M2-PK : a target of different oncoproteins
Pyruvate Kinase isoenzymes : M2-PK
Metabolic consequences of the dimeric form
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